Electrochemical Behaviour of Tropone Diiron Pentacarbonyl Complexes Fe2(CO)5[(RC2R)3CO] (R = Et, Me, n-Pr). Formation of a Carbon-Carbon Bond upon Reduction

We herein describe the electrochemical behaviour of some tropone diiron pentacarbonyl complexes Fe₂(CO)₅[(RC₂R)₃CO] (R=Et, Me, n-Pr). All these compounds exhibit a cyclic voltammetric (CV) response consisting of an electrochemically and chemically reversible one-electron reduction process at moderate cathodic potentials and a totally irreversible further reduction at c. -2 V versus SCE. At room temperature (in the long electrolysis time scale) the electrogenerated monoanion Fe₂(CO)₅[(RC₂R)₃CO]^- smoothly but completely decomposes to Fe(CO)₃[(RC₂R)₃CO]. In this process the organic chain rearranges, and a new CC bond is formed.